Targeted Knockdown of GDCH in Rice Leads to a Photorespiratory-Deficient Phenotype Useful as a Building Block for C4 Rice
Journal
Plant and Cell Physiology
Journal Volume
57
Journal Issue
5
Start Page
919
End Page
932
ISSN
0032-0781
1471-9053
Date Issued
2016-05
Author(s)
Karki,Shanta
Coe,Robert A.
Bagha,Shaheen
Khoshravesh,Roxana
Balahadia,C. Paolo
Sagun,Julius Ver
Tapia,Ronald
Israel,W. Krystler
Montecillo,Florencia
Albert de Luna
Danila,Florence R.
Lazaro,Andrea
Realubit,Czarina M.
Acoba,Michelle G.
Sage,Tammy L.
Susanne von Caemmerer
Furbank,Robert T.
Cousins,Asaph B.
Hibberd,Julian M.
Quick,W. Paul
Covshoff,Sarah
Abstract
The glycine decarboxylase complex (GDC) plays a critical role in the photorespiratory C2 cycle of C3 species by recovering carbon following the oxygenation reaction of ribulose-1,5-bisphosphate carboxylase/oxygenase. Loss of GDC from mesophyll cells (MCs) is considered a key early step in the evolution of C4 photosynthesis. To assess the impact of preferentially reducing GDC in rice MCs, we decreased the abundance of OsGDCH (Os10g37180) using an artificial microRNA (amiRNA) driven by a promoter that preferentially drives expression in MCs. GDC H- and P-proteins were undetectable in leaves of gdch lines. Plants exhibited a photorespiratory-deficient phenotype with stunted growth, accelerated leaf senescence, reduced chlorophyll, soluble protein and sugars, and increased glycine accumulation in leaves. Gas exchange measurements indicated an impaired ability to regenerate ribulose 1,5-bisphosphate in photorespiratory conditions. In addition, MCs of gdch lines exhibited a significant reduction in chloroplast area and coverage of the cell wall when grown in air, traits that occur during the later stages of C4 evolution. The presence of these two traits important for C4 photosynthesis and the non-lethal, down-regulation of the photorespiratory C2 cycle positively contribute to efforts to produce a C4 rice prototype.
Subjects
C4 rice
Glycine decarboxylase
Oryza sativa (rice)
Photorespiration
SDGs
Publisher
Oxford Academic
Type
journal article